Talk:DVD-Video

Split from DVD

Thanks for making this a new article. I was wondering whether there was a specific tag for an unfinished article as this? It does not have a lot of the basic things, like a heading and such. -- Sirius81 | Talk 16:21, 11 November 2006 (UTC)[reply]

Details of specifications

I was trying to calculate the maximum video run-time with MPEG-2, but statements like "Up to 9.8 Mbit/s" are not sufficient. —The preceding unsigned comment was added by 69.123.228.58 (talk) 22:57, 5 December 2006 (UTC).[reply]

There is no official limit in the specification for maximum movie length. There is an effective lower bitrate limit of 300kb/s ~ 600kb/s due to the hardware restrictions of most DVD players, but that is not part of the DVD-Video standard per se. (Hence why it is not directly mentioned in the article. Yet, anyway) There isn't really anything you can say about maximum run-time that is verifiable or neutral, really. -- Y|yukichigai 09:32, 6 December 2006 (UTC)[reply]

NTSC DVD horitzontal resolution should be 640 instead of 720 (?). User:Faragon 23:13, 12 December 2006 (UTC+1)

Another common misconception. Unlike newer resolution specifications, DVD-based resolutions use what could be called "odd" resolutions that are subsequently stretched during playback to the appropriate shape. 720x480 can either be "squashed" to approximate 640x480 (4:3) or "stretched" to approximate 893x480 (16:9) on playback. The rest of the resolutions are all squashed or stretched to the nearest 4:3 resolution. As for why, there's a complex mathematical reason revolving around how the numbers can be factored. Nobody's ever explained it to me in a manner that makes sense but they all assure me that its there. :P -- Y|yukichigai 05:53, 15 December 2006 (UTC)[reply]

Minimum bitrate

I think this article should also reflect both the minimum audio/video bitrates dictacted by the official DVD standard and a notation on reasonable minimum values that is expected to work on most playback devices. I have not been able to figure this out myself, which is why i ask here instead of posting the info directly. JoaCHIP 10:03, 11 January 2007 (UTC)[reply]

Officially, DVD-Video has no minimum video bitrate. The effective limit due to player compatibility seems to be between 300 and 600 kbps, but there's no citable evidence to support that. As for the audio bitrate, I believe the page lists the acceptable bitrates for each codec, save for the AC-3 codec. (which I myself am not sure of) -- Y|yukichigai 18:04, 11 January 2007 (UTC)[reply]

Professional video format

Why the first sentence states that DVD-Video is a professional video format without further explication? I believe that DVD-Video can be used for low-quality video but not for the common professional usage. Could you please provide some examples of professional applications? --pabouk 15:02, 30 March 2007 (UTC)[reply]

"Professional" here is used in the context of commercial releases, etc. Hollywood studios, the adult film industry, and other such major video production sources use DVD-Video to release their productions, hence the word "professional". By the same token, "consumer" is used because numerous pieces of easy-to-use software exist specifically for the purposes of allowing the home user to create DVD-Video content, as well as set-top DVD recorders and some digital camcorders. Both of these are generally accepted definitions or uses. -- Y|yukichigai (_ramble argue ^check) 02:19, 1 April 2007 (UTC)[reply]

I think that this usage of term professional is misleading. I have never encountered the word in a similar meaning. I would never say that VHS is a professional format although it is (or was) used in the same "professional" areas as DVD-Video. Here is an analogous example on Dolby noise reduction systems: I would say that Dolby B and C are consumer noise reduction systems while Dolby A and SR are professional noise reduction systems. Please see also professional#Equipment. Ideally the word "professional" should be removed or the article should contain an explication how was the word meant. I am not a native speaker of English so other participants to this discussion are welcome.

Simply summed up: DVD-Video is a format designed (mainly) for consumer or home equipment (like VHS) thus I would not say that it is a professional format. --pabouk 08:44, 2 April 2007 (UTC)[reply]

Framerate

The DVD specification does not permit a display framerate of 23.976 -- that isn't NTSC or PAL, it's 480p24, which is incompatible with an NTSC signal. By manipulating the RFF and TFF flags in the MPEG-2 video stream, you can trick the decoder into performing a 3:2 pulldown and converting video encoded at 23.976fps into 480i60, but the MPEG2 sequence layer must ALWAYS specify a 29.97fps framerate. The distinction between progressive and interlaced video formats and the significance of the MPEG-2 field flags is vital for anyone who is remotely interested in understanding how video assets are prepared and authored for DVD. My additions to the article were relevant, accurate, and necessary for clarity. They were neither "overcomplicated" nor "misleading" (how???) as you claim, and the fact that you perceive them as such strongly suggests that you, Yukichigai, may be be somewhat in over your head here. You speak authoritatively about the MPEG-2 and DVD specs, but you apparently don't even understand the "complex mathematical reason" for settling on the 720x480 resolution. Hence, I don't think you are in a position to arbitrate what is "overcomplicated". I have no problem with someone editing my contributions, but blanket reverts are both rude and arrogant. Azathoth68 10:39, 31 March 2007 (UTC)[reply]

It is misleading in that the initial sentence implies that the only acceptable framerate for NTSC video is 29.97. Regardless of the how, most video on NTSC DVDs is stored at 23.976.
It is overcomplicated in that it is essentially a how-to littered with specialist information that the casual reader is unlikely to care about or even understand, and Wikipedia is not an instruction manual.
Understanding the method behind 3:2 pulldown is completely unnecessary to "understanding how video assets are prepared and authored for DVD" for anybody but professionals. Exactly 0% of consumer DVD-oriented MPEG-2 encoders or DVD-Video authoring programs require an understanding of 3:2 pulldown in order to properly encode 23.976 fps video. At most, they require you to select "3:2 pulldown" from a checkbox list or dropdown menu.
The manipulation of the RFF and TFF flags, as you put it, was a deliberate design choice in the MPEG-2 spec to specifically accomidate 3:2 pulldown in DVD-Video and to remove the need for the DVD player to intelligently perform the process, as was the case with VCD and SVCD. One of the specified goals of the DVD-Video spec was to store 23.976 fps video accurately. Again, regardless of the how, the fact is that the DVD-Video spec specifically includes mention of storing video at 23.976 fps.
Your comments are grossly incivil. Personal insults (like calling me an idiot as you did above) will only get you banned. They lend nothing towards furthering your argument. -- Y|yukichigai (_ramble argue ^check) 21:19, 31 March 2007 (UTC)[reply]

Since you seem to have at least allowed the article to acknowledge that 480p24 must be effectively converted to 29.97 before it can be authored to DVD (which is far less ambiguous), and since you seem to have something of a chip on your shoulder regarding this article, I won't push the issue any farther. I will, however, respond to a couple specific things you said:

29.97 is the only acceptable framerate for NTSC. This is not a matter open for debate.
"...is essentially a how-to littered with specialist information that the casual reader is unlikely to care about or even understand..." I'm glad that you have such unique insight into the "casual" reader. This article is a technical article describing the Book B spec, including citing bitrate and framerate requirements. One could very easily argue that this whole article is 'specialist information'. Refusing to include two additional sentences that correct a mild innaccuracy and elucidate how non-NTSC material is encoded on an NTSC disc simply because you've decided it's 'technical' is arrogant and absurd.
"Understanding the method behind 3:2 pulldown is completely unecessary to "understanding how video assets are prepared and authored for DVD" for anybody but professionals. Exactly 0% of consumer DVD-oriented MPEG-2 encoders or DVD-Video authoring programs require an understanding of 3:2 pulldown in order to properly encode 23.976 fps video." This amazingly broad statement is not only wrong, but it also represents something of a value judgment on your part: "Some cheap encoders don't require people to understand 3:2 pulldown, so therefore I refuse to include a sentence about that in the article." In fact, some low-end "consumer DVD-oriented" software products don't even require you to specify a bitrate. You simply select low, medium, or high quality, and they spit out a finished dvd image. Using your flawed logic, I could argue that the talk of bitrates is overly technical and should be removed from the article. The purpose of Wikipedia is to expand practical knowledge, not limit it. Your attitude of "I'll decide what the reader wants to see and doesn't want to see" is inimical to Wikipedia's goals.
The MPEG-2 spec was developed and finalized before Book B was. Yes, the frame flags were designed in part to allow 3:2 pulldown, but they have other uses as well, including allowing framerates other than 23.976 to be pulled down to something close to 480i60 on a DVD. This isn't just theory, it is actually done. 23.976 is NOT the only progressive framerate that can be used when preparing an NTSC dvd.
My comments were entirely justified in light of your initial uncivil behavior. Quoting Wiki policy and etiquette to me isn't really helpful, as you yourself are in direct violation of it and risk getting banned. [1][2] Azathoth68 05:51, 1 April 2007 (UTC)[reply]

For the record, this is largely correct. NTSC DVDs must play on standard NTSC TVs, which can only handle 29.97 fps. Therefore, 29.97 fps is the only allowed "display" frame rate. It's true that the spec explicitly refers to 23.976 framerate, but this is largely because it's the most common framerate from film. MPEG field flags can actually be used a handle a variety of source frame rates such as 24.0 fps, 25 fps, 15 fps, etc., each with its own pulldown cadence. JimTheFrog 09:53, 18 July 2007 (UTC)[reply]

Region Codes

Concerning this sentence in the Region Codes section: Laws in the United States specifically prohibit the domestic sale of DVD players which are not set to Region 1 by default.
What laws, or is the effect accomplished by licensing agreements? It seems hard to believe congress has the authority to regulate something like this. AnotherBrian 13:20, 5 April 2007 (UTC)[reply]

I agree. I don't know of any laws for region coding. I will revise the section to refer to the CSS license, which is what is used to enforce region coding. JimTheFrog 07:53, 9 April 2007 (UTC)[reply]

Frame rate and other requirements

"Professionally encoded videos average a bitrate of 3.5 Mbit/s with a maximum of 7-8 Mbit/s in high action scenes. Although this is typically done to enable greater compatibility amongst players, and to help prevent buffer underrun in the case of a dirty or scratched disc."

Does that second sentence make sense? Number one: it's a fragment sentence, number two: what is it talking about? The previous sentence looks like it's just listing the usual bitrate for professional production just in case someone is wondering. Maybe this sentence is referring to the bit about the raw dvd bitrate. You guys think it should be moved or edited or something? I think this paragraph and the previous one might have been one run-on sentence that someone split up. Gamingexpert13 09:47, 14 June 2007 (UTC)[reply]

Anti-rip (Arccos)

Arccos is not part of the DVD-Video standard, and there are other anti-rip alternatives, so I have made changes accordingly. JimTheFrog 09:57, 18 July 2007 (UTC)[reply]

multiple languages & NTSC-centric view?

For this reason, many discs are made with at most two audio languages to allow single-layer discs to be used.

As I understand it, the (slight) majority of PAL discs are dual layer. It's usually mentioned on the back cover. Most of my experience comes from Nordic editions (2x original-language audio, 4x subtitles, menus unlocalised or frugal if localised). A reference I googled says dual-layer discs are prevalent in Australia, too [3] (under "Compression ratio")

The text also seems to conveniently ignore the (bothersome) fact of region coding (no need to include languages that are not part of the target region), markets smaller than a region, and that multi-language releases are more expensive and slower to co-ordinate. --MinorContributor 21:34, 20 July 2007 (UTC)[reply]

DVD Languages

Whoever wrote that DVDs don't often have more than one or two languages has never bought an Asian DVD. http://en.wikipedia.org/wiki/DVD-Video#Frame_rate_and_other_requirements Most of the DVDs I buy have at least 3 languages and on average 4 (Cantonese, Mandarin, Thai, and Japanese, sometimes with Mongolian or Farsi as well) for audio alone; along with a half dozen subtitles. Lostinlodos 08:58, 4 August 2007 (UTC)[reply]

This is not only true of Asian DVDs, it's also the case with European (or certainly British) ones which have on average 3 and sometimes many more language options for their soundtracks and many more for their subtitles. Andypreston (talk) 13:21, 30 November 2009 (UTC)[reply]

Bits per pixel?

How many bits are used to represent each pixel's RGB + luminance values on the screen? 32? 24? - Theaveng 17:38, 6 September 2007 (UTC)[reply]

In almost all cases, 12 bits, as the video is YV12 format, not RGB. —Dark•Shikari^[T] 23:22, 14 November 2007 (UTC)[reply]

Average Bitrate == 3.5 Mbit/sec?

"Professionally encoded videos average a bitrate of 3.5 Mbit/s...." Where did this come from? I don't see a citation or source. My own personal observations disagree with the statement, because my DVDs seem to hover around 5 Megabits/second, and that's why I'm wondering where this statistic came from. - Theaveng 17:45, 6 September 2007 (UTC)[reply]

I agree that it is inaccurate, more like 5 Mbit/s or so. --Ray andrew 13:47, 7 September 2007 (UTC)[reply]

High quality Video DVDs come with 8Mbps video rate and low ones with 3Mbps and the

rest is in between -- Michael Janich (talk) 09:10, 7 December 2007 (UTC)[reply]

Pixel aspect ratios

Could someone please write about the pixel aspect ratio of 1.1:1 in PAL/4:3 and 1.xx:1 in PAL/16:9... It's an important aspect if you design an image for a DVD and you want all the circles to be round. THANKS -- Michael Janich (talk) 09:10, 7 December 2007 (UTC)[reply]

No historical information

This article completely lacks any historical background on DVD video. I will try to research this and add it, but it really needs something besides a factoid of when it eclipsed VHS. -Rolypolyman (talk) 21:31, 16 February 2008 (UTC)[reply]

I agree. There is no information about the development of the technology; there's a lot of this in the main DVD article, but it should be at least summarized here. In addition, info should be available about the manufacturers (who was first to market with a DVD player), titles (what was/were the first DVD title(s)?), etc. There should also be some discussion of the development of successful categories of DVD video software that didn't exist (or were rare) on tape, like box sets and TV series anthologies. I've heard that The X-Files was the first TV series released as a DVD set, but don't have any corroborating references for this (even the X-Files article doesn't mention it). EJSawyer (talk) 18:22, 30 March 2009 (UTC)[reply]

File system?

Which file system does DVD-Video use? Maikel (talk) 08:49, 18 February 2008 (UTC)[reply]

Universal Disk Format --MinorContributor (talk) 17:13, 18 May 2009 (UTC)[reply]

Citations

Hi, I've added a couple of citations about the arrest and legal wrangle over DeCSS. The other statement that needs citation is one about "the vast majority of DVDs using AC-3" (rather than DTS). Anyone got any numbers, stats, sales figs we can point to? Jon (talk) 01:31, 18 June 2008 (UTC)[reply]

Packaging

There's no information about the various types of DVD packaging (Keep Cases, Snapper Cases, Steelbooks etc.) in this article. —Preceding unsigned comment added by 86.43.64.115 (talk) 15:54, 20 August 2008 (UTC)[reply]

Confused consumers?

Due to multiple audio (and video) output sources, a consumer has many outputs on a DVD player, and may become confused with connecting their player to their TV and/or amplifier.

You should NOT write opinions to dictionary, because not all DVD users are americans and being confused with anything requiring common sense!

Someone, rephrase please. —Preceding unsigned comment added by 72.144.149.241 (talk) 11:25, 13 February 2009 (UTC)[reply]

Image:DVD-Regions_with_key.png

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MP2 Audio Max Bitrate

Are you sure of the quoted bitrate for MP2 Audio: MP2: 48 kHz sampling rate, 1 to 7.1 channels, up to 912 kbit/s?

Shouldn't this be 192 Kbit/s?

Andypreston (talk) 11:57, 15 September 2009 (UTC)[reply]